Method of making side seam sealed container



Feb. 17, 1970 H. J. HAAS am 3,495,501

l METHQD OF IAKING SIDE SEAM SEALED CONTAINER Filed April 5, 1967 FIGLI.

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HEAT AIVD PRESSl/Rf BOND 4| United States Patent Ofce 3,495,507 Patented Feb. 17, 1970 3,495,507 METHOD OF MAKING SIDE SEAM SEALED CONTAINER Henry J. Haas, Scarsdale, N.Y., and Leon W. La Bombard,

Nashua, N.H., assignors to International Paper Company, New York, N Y., a corporation of New York Filed Apr. 5, 1967, Ser. No. 628,709 Int. Cl. B31b 1/64, 3/60; B31f 7/00 U.S. Cl. 93-94 6 Claims ABSTRACT OF THE DISCLOSURE BACKGROUND OF INVENTION The packaging in paperboard containers of fluids such as soft drink syrups raises problems of leakage both into and out of the container. The containers are made of coated paperboard, scored and folded to the desired shape. The blanks for the containers are cut from the paperboard and thus have unsealed edges. If the fifth or sealing panel is on the inside, the contained fluid wicks into the raw edge weakening the container so that it may rupture under stress. If the sealing panel is on the outside, unwanted foreign material may leak into the container byy wicking.

Efforts have been made in the past to inhibit and hopefully to stop this leakage with mixed results. The uncoated edges have been coated with sealing material. The coating on one face and the paperboard have been removed in a strip and the remaining coating folded over. The edge portions of the container material have been skved and folded together with intervening adhesive. Feather edge or tapered skiving has also been used.

Summary of invention Containers of the kind contemplated are made from blanks of paperboard coated with a substantially impervious layer or film of a plastic material such as polyethylene or another plastic having suitable qualities. Many containers of this kind are of rectangular section, usually square. For making such a container the blank is scored to define four side wall panels and a relatively narrow side sealing panel sometimes called the fifth panel. The blank s further scored to divide each panel into top, body, and bottom or end sections.

In order to better solve the noted problems of making coated paperboard containers, it is proposed in accordance with this invention to prepare the container blank for assembly by skiving a strip on the sealing or the fifth panel to a depth equal to half the thickness of the blank. A line is then scored down the middle of this strip on its unskived face dividing it into two parallel, halfwidth strips. The skved portion is then folded on the scored line so that the skved faces are in contact. Since the skived portion of the strip is half thickness and the strip portions anking the scored line are equal in width, the edge of the strip when folded fits tightly against the edge of the ledge formed by skiving and the folded portion is of the same thickness as the main stock. Because of the scoring and of the snug fit, no adhesive s needed in the fold.

However, it is important that the fold line be ironed to reduce the spring-back tendency and thus keep the fold from unfolding through the heat activation period.

The side seam panel, which is bounded on its inner edge by a scored line between it and the adjacent body panel, is folded on this line to fit against a mating panel. The direction of the folding is such that the folded-over portion of the skved strip makes contact with the mating panel. Thus if the iifth panel is on the inside the folding is in one direction and if on the outside, in the other direction, and it is scored accordingly.

The sealing seam is wider than the folded over skved strip by enough to obtain a bond beyond this strip. This part of the sealing seam may be as wide as or somewhat Wider than the folded strip. The sealing may be accomplished by the application of heat and pressure to the mating portions of the folded blank. The top and bottom portions of the container are formed on their scored lines and suitably sealed.

Brief description of drawing The features of this invention will be understood more fully and clearly from the ensuing description of illustrative embodiments thereof taken in connection with the appended drawings in which:

FIG. 1 shows a container blank on which the location of the scored lines and of the skived portion are indicated;

FIG. 2 is a perspective view of the erected container;

FIG. 3 is a section of the blank showing the location of skved and scored portions;

lFIG. 4 is a section similar to FIG. 3 but with half of the skved portion folded -unto the other half;

FIG. 5 is a section on line 5-5 of FIG. 2 showing a side seam assembled with the sealing or fifth panel inside the adjoining body panel; and

FIG. 6 is a section similar to that of FIG. 5 but with the sealing panel outside of the adjoining body panel.

Description of illustrative embodiments As seen in FIG. l, the blank 10 comprises the four body panels 11, 12, 13 and 14, and the side seam panel 15. I'he panel 15 has a strip skved over a portion of its width as indicated by 16 as is more fully shown in FIG. 3. The side wall portions of the blank are denoted as 11W, 12w, 13w and 14W. The portions of the top and bottom or end of the container are denoted as 11i, 122', 13t and 14t and 11e, 12e, 13e and 14e, respectively. The location of some of the necessary scored lines is indicated by dotted lines 18, 19, 20 and- 21.

FIG. 2 shows the assembled container in perspective. The side seam panel is on the inside and its edge is indicated by the dotted lines. The reference characters correspond to those of FIG. l.

The sectional view of a portion of the container blank shown in FIG. 3 indicates where the side seam panel 15 has been reduced up to the shoulder 15a by skiving. The skiving removes material down to essentially half the thickness of the blank leaving a half thickness portion 16. A line 17 is scored down the middle of the skved strip on its coated side and parallel to the scored line 18 at the intersection of the panels 14 and 15.

In the view of FIG. 4, the skved strip 16 is bent on the scored line. 17 so that the skved faces are in contact. The edge of the strip 16 ts snugly against the shoulder 15a of the full thickness portion of the fifth panel 15. Because of the scored line 17 and a good fit, no adhesive is required in this fold. However, the fold line 17 should be ironed, as by passing the blank between a pair of rollers after the fold has been made, as shown in FIG. 4, to reduce the tendency for the end of panel 16 to spring 3 back. Such ironing keeps the fold from unfolding during the heat activation period.

A corner joint between the side sealing panel 15 and the side wall panel 11 is shown in FIG. 5. The side wall or body panel 14 is shown as bent on the scored line 18.

This represents a corner with the fifth panel 15 inside of the container.

In FIG. 5, the laminae of the coated paperboard are denoted. The plastic coatings 11a and 11C are on opposite faces of the paperboard 11b. This of course applies to the Whole blank and not only to what is disclosed on panel 11.

In FIG. 6, the fifth panel 15 is represented as outside of the first panel 11. In order that this may be done a scored line 18a may be made on the side of the blank 10 opposite to the line 18 as it is shown in FIGS. 3 and 4.

The joint is bonded by the application of heat and pressure thereto by conventional means for sealing containers of this kind. It will be noted in the joints of both FIGS. 5 and 6 that the folded over portion 16 of the panel is between 1S and the panel 11 to which it is sealed. It will be further noted that the bonding includes a portion of the panel 15 thathas not been skived and is therefore of the full thickness of the blank. In FIG. 6 the edge of the panel 11 butts tightly against the side of the panel 14. Thus, a strong leak-proof joint is afforded.

The foregoing is a description of illustrative embodiments of the invention and is not intended as a limitation on what is claimed.

What is claimed is:

1. The method of sealing the side seam of a container formed from a blank of foldable, fibrous sheet material coated with a plastic layer on each face, and having a plurality of scored lines dividing the blank into five contiguous panels including first, second, third and fourth side wall panels, and a side seam panel, which comprises skiving a strip on one surface of said side seam panel along the free edge of said side seam panel to a substantially uniform depth equal substantially to one-half of the panels thickness thereby to provide a skived surface parallel to the unskived surface of said side seam panel and a shoulder parallel to said free edge of said side seam panel, scoring a line down the middle of said strip on its other surface to divide said strip into two equal portions, folding the skived strip upon itself with the skived surfaces of said portions in contact, said folding being along said scored line to insure alignment of said equal portions and abutment of said free edge of said strip against said shoulder, and applying heat and pressure to seal the unskived surface of the folded strip and an adjacent strip of the side seam panel to a surface of the first side wall panel.

2. The method of sealing the side seam of a container as in claim 1 comprising the additional step of ironing the folded skived strip prior to Said step of applying heat and pressure.

3. The method of sealing the side seam of a container as in claim 1 in which the skiving is done on the outside of the side seam panel so that the folded over portion is in contact with and sealed to the first side wall panel on its inside surface.

4. The method of sealing the side seam of a container as in claim 1 in which the skiving is done on the inside of the side seam panel so that the folded over portion is in contact with and sealed to the first side wall panel on its outside surface,

5. In a method of making a fluid container, the steps comprising selecting a blank of foldable plastic coated sheet material, scoring the blank to define side Wall panels and a side seam panel, skiving the side seam panel in a strip adjacent a free edge thereof to a substantially uniform depth equal substantially to half its thickness thereby to provide a skived surface parallel tothe unskived surface of said side seam panel and a shoulder parallel to said free edge of said side seam panel, scoring a fold line in the center of said strip to divide said strip into two equal portions, folding said strip so that the skived surfaces of said portions are in contact, said folding being along said score line to insure alignment of said equal portions and abutment of said free edge of said strip against said shoulder, ironing said folded strip, and sealing the ironed, folded over strip and an adjacent strip of the side seam panel along the free edge of a mating side wall panel so that the folded over strip is within the seam.

6. The method of sealing the side seam of a container formed from a blank of foldable, fibrous sheet material coated with a plastic layer on each face, and having a plurality of scored lines dividing the blank into five contiguous panels including first, second, third and fourth side wall panels, and a side seam panel, said first side wall panel and saidy side seam panel being outside panels and each having a free edge, which comprises skiving a strip on one surface of one of said outside panels along and adjacent the free edge thereof to a substantially uniform depth equal substantially to one-half of the panels thickness thereby to provide a skived surface parallel to the unskived surface of said one panel and a shoulder parallel to lsaid free edge of said one panel, scoring a line down the middle of said strip on its other surface to divide said strip into two equal portions, folding the skived strip upon itself with the skived surfaces of said portions in contact, said folding being along Said score line to insure alignment of said equal portions and abutment of said free edge of said strip against said shoulder, and applying heat and pressure to seal the -unskived surface of the folded strip and an adjacent strip of the panel in which said strip is formed to a surface of another one of said panels.

References Cited UNITED STATES PATENTS 1,062,002 5/1913 Harbeck 93-94 1,281,356 10/1918 Harbeck 93-94 1,698,532 1/1929 Brooks 93-94 2,152,323 3/1939 Moore 93-35 2,190,479 2/ 1940 Moore 93-77 '2,196,666 4/1940 Moore 93-39.1 2,799,211 7/1957 Zerlin 9349 3,058,868 10/ 1962 Schroeder 93-36 3,234,858 2/1966 Rein 93-36 3,335,540 8/1967 Reil 93-84 1,805,735 5/1931 Kurtz.

2,268,668 1/1942 Moore 93-59 3,242,829 3/1966 White 93-94 3,444,792 5/ 1969 Thesing 93-35 WAYNE A. MORSE, JR., Primary Examiner U.S. Cl. X.R. 

